The present invention relates to a technique for improving temperature characteristics of an optical transmission module. In particular, the technique can be suitably applied to a can type optical module.
In an optical communication module that uses an optical fiber, a laser diode (hereinafter abbreviated as LD) which is a luminous element, and a photodiode (hereinafter abbreviated as PD) which is a light receiving element, are accommodated in various kinds of packages from the view point of reliability. Among the packages, there is a can type package that can easily have a coaxial structure with an optical fiber. This can package is often used as a receptacle type optical transmission module, into which an optical fiber is inserted, and from which the optical fiber is removed (for example, refer to Japanese Patent Laid-Open No. 2001-66468).